PATCH TEST STUDY WITH CALCIPOTRIOL OINTMENT IN DIFFERENT PATIENT GROUPS, INCLUDING PSORIATIC PATIENTS WITH AND WITHOUT ADVERSE DERMATITIS

One hundred and sixty-eight individuals (psoriatic patients treated wi th calcipotriol with dermatitis due to calcipotriol, psoriatic patient s treated with calcipotriol with no dermatitis, psoriatic patients nev er treated with calcipotriol, patients with eczema and healthy volunte ers) were patch-tested (Finn chambers, back, 48 h) with dilutions of c alcipotriol ointment (50, 10, 2, 0.4 mu g/g) and an ointment vehicle, Test evaluation was based on clinical scoring and various non-invasive measuring methods. Doubtful (?+) and weak (1+) reactions were common, irrespective of patient group and history, Moderate (2+) reactions we re uncommon and with no increased frequency among psoriatic patients w ith adverse dermatitis during calcipotriol treatment, The blood how of test sites measured by laser Doppler flowmetry was, however, increase d in psoriatics, who developed dermatitis during calcipotriol treatmen t as an isolated finding, Furthermore a 1-week repeated open applicati on test (ROAT) was performed on an subjects, None of the persons havin g a strong reaction in the patch test showed any dermatitis in the ROA T test, indicating that they were not sensitized, Calcipotriol eas fou nd to be a mild irritant of the non-corrosive type, i.e, dth no influe nce on the skin barrier, Reactions were dominated by redness (increase d laser Doppler floe and chroma a) and only oedema formation in advan ced reactions. The calcipotriol dose-irritation curve was found to be scattered, Calcipotriol induced no increase of transepidermal water lo ss (TEWL) versus the ointment vehicle, but the ointment vehicle itself increased TEWL. The special ointment vehicle needed for calcipotriol for stability reasons may itself be irritant and cause some impairment of the skin eater barrier, with increase in TEWL values. Future patch test studies for calcipotriol allergy should not be done with this ve hicle, The non-irritant threshold concentration of calcipotriol in an appropriate test vehicle is still unknown.